Internal combustion engine



March 5, 1935. E NlBBS 1,993,179

INTERNAL COMBUSTION ENGINE Filed Oct. 17, 1932 r l a s s l l f l, l i 1 -v Illllll/l u injection engines.

Patented Mar. s, 193s INTERNAL COMBUSTION ENGINE Ernest Nibbs, New London', Conn., assgnol' to Electric Boat Company, Groton, Conn., a corporation of New Jersey 1 Application October 17,

This invention relates to internal combustion engines, and has to do with injection engines.

In general, my invention is directed to increased efliciency and smoothness in operation of More specifically, the object of my invention is to provide high turbulence and increased volumetric eiciency, assuring thoroughmixing of the injected fuel with the air charge and rapid flame propagation with resulting increase in power and efliciency. Further objects and advantages of my invention Will appear from the detail description.

In the drawingz- I Figure 1 is a horizontal sectional View through an engine embodying my invention, taken in a plane adjacent the top of the cylinder;

Figure 2 is a section taken substantially on line 2-2 of Figure 1, on a reduced scale, parts being shown in elevation;

Figure 3 is a section taken substantially on line 3-3 of Figure 1, on a reduced scale, parts being shown in elevation.

I have illustrated my invention, by way of example, as applied to' an engine comprising a cylinder block 1, a head 2 mounted upon the cylinder block in a known manner, a cylinder 3 and a piston 4 operating in the cylinder, the headand the cylinder block being water jacketed in a known manner. The head may be formed separately from the cylinder block, as shown, or may be formed integrally therewith, as is known in the art.

Head 2 is provided with an offset 5 defining a pocket 6 disposed to one side of the cylinder 3. This pocket tapersl in height toward its outer end, as in Figure 2, and is of approximately involute shape in plan. Head 2 is provided with a lower Wall 7, the under face of which is ilat, this wall overlying the cylinder area and the pocket y6. Two air inlet passages 8 extend through the' head and open into the cylinder through wall 7. These passages are controlled by air inlet valves 9 of known type, the stems 10 of which are parallel,

with the cylinder axis. The head is further provided with an exhaust passage 1l for the burnt gases, which passage is controlled by an overhead valve 12 located adjacent the outer end of pocket 6, stem 12a of this valve being parallel with the cylinder axis. The valves 9 and 12 are operated in timed relation in a manner well known in the art and which -need not be illustrated nor described here, it suicing to note that suitable means is provided :for operating the valves. If desired, the two air inlet valves 9 may be replaced by a single valve of suitable area. By having the 1932, Serial No. 638,061

exhaust valve 12 disposed to one side of the cylinder area, the area available for admission of charging air to the cylinder is much greater than would otherwise be the case, which is advantageous as contributing tothe volumetric eiliciency of the engine.

The pocket 6' comprises a surrounding Wall which includes a portion 13 of regular curvature and which extends concentrically withthe center of the outer portion of the pocket through 10 an are of approximately 245 degrees, from the` point 13a to the point 13b. One end of this regularly curved wall 13 is connected by a relatively short element 14, tangent thereto, to the cylinder wall. The other end of wall 13 is con- 15 nected by a relatively long wall 15 to the side 0f the cylinder wall, wall 15 being tangent to the cylinder and to wall 13. Piston 4 is provided,

in the head thereof, with a segmental depression 16 disposed to register with the inner end 25- of pocket 6 when the piston is in its position of maximum compression, that is, in its upper dead center position. When the piston is in its uppermost position, the clearance space 17 between the upper end of the piston and the under face 30,

of wall 7 of the head is the minimum required for mechanical consideration 4and is ineective as combustion space. With the piston in its full raised position, pocket 6 and depression 16 define a combustion space or chamber of approxi- 35 mately triangular shape in plan and constitute all of the effective combustion space when the piston is in said position. Wall 15 is slightly curved, the radius of curvature of this wall being much greater than the radius of curvatureof Wall 13. Since the pocket opens into the cylinder tangentially thereof, and the radius of curvature of the pocket decreases toward its outer end, gases entering the pocket from the cylinder during the upstroke of the piston will have a rotative movement imparted thereto and the velocity of this movement increases toward the outer end of the pocket with the result that such gases or air are caused to whirl or rotate in the outer` portion of the pocket, and in the area'I cor- 50 responding to that of valve 12, at high velocity. This rotating or whirling effect may be increased by imparting to the entering air charge rotative movement in the' cylinder toward the wall 15 of the pocket which is tangent to the cylinder 55 wall. This result may be accomplished in various ways, though I preferably provide each of the v valves 9"with an arcuate shroud 18 mounted on the upper face of the valve and tting into the lower end of passage 8. The height or this shroud o0 thereof.

is preferably slightly greater than the downward movement of the valve in the opening thereof.

, The valves 9 are opened during the suction stroke of the piston and the entering air charge is directed, by the shroud 18, toward the cylinder wall and in the general direction of wall 15 of the pocket, the shroud being suitably disposed for this purpose and approximately as indicated in Figure 1. f

.During the downward or suction stroke of the piston, the entering air ,charge rotates in the piston in a counter-clockwise direction as viewed in Figure 1 and in the succeeding compression stroke of the`piston this air is forced into pocket 6, following along wall 15 with increasing lvelocity and around the wall 13 into the space enclosed thereby, in which space the air is caused to whirl or rotate at high velocity. As the piston reaches the limit of -its upward stroke, the remaining air charge is forced from between the upper end of the piston and wall '7 into the pocket 6 at greatly increased velocity,u thus materially increasing the velocity of rotation of the air in the outer end portion of the pocket. In this manner, I assure high turbulence of the air charge as the piston` reaches the end of its compression stroke.

An injection nozzle 19 is suitably mounted in a boss 20 opening into pocket 6 at the outer end This nozzle is of known type and liquid fuel is supplied to the nozzle under pressure in a known manner, suitable means, known in the art, being provided for opening the nozzle for injection of fuel into pocket 6 as the piston aproaches its uppermost position. The disposition of the spray nozzle 19 is such that the' injection fuel enters the pocket approximately at right angles to the direction of flow of the air charge in the outer portion of the pocket, it being noted that at this irne the charge of air in the outer portion of the pocket is rotating at high velocity and in a counter-clockwise direction as viewed in Figure 1. The injected fuel is thus swept by the rotating air charge so as to be thoroughly and intimately intermixed therewith, which is conducive to complete and rapid combustion with resulting efficiency in operation, due to increased power output and smoothness. Upon injection of the fuel, combustion occurs and, during the resulting downstroke of the piston, the burning mixture of fuel -and air flows out of the pocket and along the Wallv 15 into the cylinder. 'As a result, the body of mixture within the outer portion of the pocket is caused to rotate at high velocity in a clockwise direction. The injection of fuel continues during the first portion of the power strokead 'the entering fuel is now swept by the ,burning mixture of air van'd fuel so as to be intimately intermixed therewith, `thus assuring thoroughv combustion with resulting increased efficiency. It is also to be noted that the injection nozzle 19 is so Vdisposed that the injected fuel has an unobstructed path of -fiow along the center line of injection, corresponding to the line mof Figure- 1, through a distance greater than the diameter of cylinder 3. This is advantageous as contributing to thorough'mixing of the fuel with the air charge and the mixture of fuel and air. While I preferably dispose the injection nozzle as illustrated in Figure 1, this nozzle can be.

disposed in various positions so long as the above conditions as to thorough mixing of the fuel and air and the length of the path of unobstructed travel of the injected fuel are complied with.

.high speed and'is in contact with the exhaust valve. In 'this manner the exhaust valve is cooledv tov a. certain extent, 'which is desirable, and the heat thus extracted from the exhaust valve is utilized for heating and vaporizing the injected fuel, which is conducive to rapid and complete combustion of the charge.

While I have illustrated my invention, by way of example, as applied to an engine operating on the four-stroke cycle, it is capable', in its broader aspects, of being used with engines oper'- ating on the two-stroke cycle, and I do not, therefore, intend to limit my invention to the former type of engine. Also, while I preferably provide the piston 4 with a segmental depression 16 in the head thereof, as illustrated and described, this is not essential in all -cases and I contemplate omitting this depression if desired or Where conditions may require. In ether case, the pocket 6 is properly proportioned relative to the effective cylinder volume to'assure high turbulence of the air charge and the fuel mixture, in the manner above described, and also to assure ignition of the fuel injected into the pocket and cylinder as the piston approaches or reaches its position of maximum compression.

As above indicated, and as will be understood by those skilled in the art, changesI in construction and arrangement of parts of my invention may be resorted to without departing from the eld and scope of the same, and I intend to include all such variations, as fall within the scope of the appended claims, in this application, in Y which the preferred form only of my invention is disclosed.

What I claim isz'- l. In combination in an internal combustion engine of the injection type, a cylinder and a piston operating therein, a pocket to one side of and opening into the cylinder substantially tangentially thereof. said pocket comprising va surrounding wall, said Wall comprising a first portion remote from the cylinder and approximating a semi-circle and a second portion connecting and `tangent to said first portion and said cylinder, a burnt gas exhaust passage opening into the pocket, and exhaust valve in the pocket and controlling said passage, valve controlled means for admitting air into the upper end of the cylinder and for causing the entering air to flow substantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket.

2. In combination in an internal combustion engine of the injection type, a cylinder and a piston operating therein, a pocket ts one side of and opening into the cylinder substantially tangentially thereof, said pocket comprising a surrounding wall, said wall comprising a rst portion remote from the cylinder and approximating a semi-circle and a second portion connecting and tangent to said first portion and said cylinder, the piston being provided in the head thereof with a segmental depression disposed to register with the inner end of the pocket and form a continuation thereof when the piston is in its position of maximum compression, a burnt gas exhaust passage opening into the pocket, an exhaust valve in the pocket and controlling said passage, valve controlled means for admitting air into the upper end of the cylinder and for causing the entering air to flow substantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket.

3. In combination in an internal combustion engine of the injection type, a cylinder and a piston operating therein, a pocket to one side of and opening into the cylinder substantially tangentially thereof, said pocket comprising a surrounding wall, said wall comprising a first portion remote from the cylinder and approximating a semi-circle and a second portion connecting and tangent to said rst portion and said cylinder, a cylinder head having aat lower wall overlying the cylinder area and the pocket, the clearance between the piston and the under face of said wall being the minimum required for mechanical considerations when the piston is in its position of maximum compression, said piston being provided in the head thereofkwith a segmental depression disposed to register with the inner end of the pocket and form a continuation thereof when the piston is in said position of maximum compression, the pocket andthe depression together defining all of the effective combustion space when the piston is in its position of maximum compression, a burnt gas exhaust passage opening into the pocket, an exhaust valve in the pocket and controlling said passage, valve controlled means for admitting air into the upper end of 'the cylinder and for causing the entering air to flow substantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket.l

Il. In combination in an 'internal combustion engine of the injection type, a cylinder and a piston operating therein, a pocket to one side of and opening into the cylinder substantially tangentially thereof, a burnt gas exhaust passage opening into the pocket, an exhaust valve -inthe pocket and controlling said passage, valve controlled means for admitting air into the upper end of the cylinder and for causing the entering air to owsubstantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket, the injecting means being so related to the pocket that the distance from the point of injection to an opposite pointon the cylinder Wall, taken along the center line of injection, is greater than the diameter of the cylinder.. z

5. In combination in an internal combustion engine ofthe injection type, a cylinder and a piston operating therein, a pocket to `one side of and opening into the cylinder substantially tangentially thereof, a burnt gas exhaust passage opening into the pocket, an exhaust valve in the pocket and controlling said passage, valve controlled means for admitting air into the upper end of the `cylinder and for causing the entering air to flow substantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket, the injecting means being so related to the pocket that the distance from the point of injection to a point on a wall opposite to said point of injection, taken along the center line of injection, is greater than the diameter of the cylinder.

6. In combination in an internal combustion engine of the injection type, a cylinder and a piston operating therein, a pocket to one side of and opening into the cylinder substantially tangentially thereof, valve controlled means for admitting air into the' upperl end of the cylinder and for causing the entering air to flow substantially circumferentially of said cylinder toward said pocket, and means for injecting fuel into the pocket and the cylinder, the injecting means being so related to the pocket thatthe length of the path of unobstructed flow of the injected fuel, taken along the center line of injection, is greater than the diameter of the cylinder.

ERNEST NIBBS. 

